If your husband was not overweight to begin with, and most of us are not, then you might ask your doctor or gastroenterologist about giving him TPN and Lipids infusion. It will replace all the nutrients that he is losing, and he would not have to worry about eating food.
I am an ovarian cancer patient, on chemo, and after surgery, I was depleted and we did not think that I was going to make it this time. I was put on TPN and Lipids infusion for about 3-4 weeks daily. It put my health back to where it was and then some. Be sure to check with insurance company to see if they pay for it. It is expensive, but if you can do it, it's worth it. Rosy cheeks will soon appear.
Tell your husband to hang in there. And you take care of yourself too.
Hugs,
Vicki in Wylie